Anodizing titanium — color by voltage
No dyes, no pigments — anodized titanium colors are pure physics. The voltage-to-color chart, and what it means for specifying parts.
How it works
Applying a voltage to titanium in an electrolyte grows a transparent oxide layer. Light reflecting off the top and bottom of that layer interferes — the same physics as a soap bubble — and the eye reads a color. Thicker oxide (higher voltage) shifts the color through the spectrum. Nothing is deposited; the color cannot chip or fade.
The voltage-to-color chart (Grade 2)
| Voltage | Color | Oxide thickness |
|---|---|---|
| 10–15 V | Bronze / brown | ~5–8 nm |
| 18–22 V | Purple-blue | ~10–14 nm |
| 25–30 V | Cobalt blue | ~20–25 nm |
| 30–40 V | Light blue | ~28–35 nm |
| 50–55 V | Gold / yellow | ~55–62 nm |
| 65–75 V | Magenta / violet | ~68–80 nm |
| 85–95 V | Teal / green | ~90–110 nm |
Grade 5 shifts darkerAlloying elements mute the effect: the same voltage on Grade 5 gives a darker, more antique tone than on Grade 2. Specify by sample, not by voltage alone, when color must match across parts.
Specifying color for production
- Give your supplier a physical reference part, or agree on a voltage + electrolyte + dwell time recipe and keep it frozen.
- Surface finish changes perceived color — anodize after final finishing, on identically-prepared surfaces.
- True black is NOT anodizing — black titanium is PVD or DLC coating. Red does not exist in the spectrum.
- Anodizing is cosmetic + identification (medical coding, bike brand colors). It does not significantly change corrosion resistance, which is already excellent.
Bronze 12V10–15 V
Blue 30V25–35 V
Gold 52V50–55 V
Magenta 70V65–75 V
Teal 90V85–95 V
Updated 2026-09
Want color on production parts? Specify it with your quote.
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